Efficiency enhancement in two-cell CIGS photovoltaic system with low-cost optical spectral splitter Maragliano, Carlo ; Apostoleris, Harry ; Bronzoni, Matteo ; Rampino, Stefano ; Stefancich, Marco ; Chiesa, Matteo Abstract Publication: Optics Express Pub Date: January 2016 DOI: 10.1364/OE.24.00A222 Bibcode: 2016OExpr..24A.222M